Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing
virtus
Group Title
Find the volume of the solid formed when the area bound by the curve y=4x^2 and the x axis is rotated one complete revolution about the y axis
 2 years ago
 2 years ago
virtus Group Title
Find the volume of the solid formed when the area bound by the curve y=4x^2 and the x axis is rotated one complete revolution about the y axis
 2 years ago
 2 years ago

This Question is Closed

sauravshakya Group TitleBest ResponseYou've already chosen the best response.0
first find the critical points and use integration
 2 years ago

amistre64 Group TitleBest ResponseYou've already chosen the best response.1
or just consider one side of it
 2 years ago

virtus Group TitleBest ResponseYou've already chosen the best response.0
can you just tell me the answer , because i am getting the wrong answer. I got 16 pi units but the answer is 8 pi units and i don't know where i went wrong.
 2 years ago

amistre64 Group TitleBest ResponseYou've already chosen the best response.1
please dont ask for "just an answer"
 2 years ago

amistre64 Group TitleBest ResponseYou've already chosen the best response.1
dw:1342094312271:dw this can be done by shells or disks; which way are you most comfortable with?
 2 years ago

amistre64 Group TitleBest ResponseYou've already chosen the best response.1
i think i know why youre twice as big as the answer; your prolly integrating the whole thing across
 2 years ago

amistre64 Group TitleBest ResponseYou've already chosen the best response.1
your in effect sweeping the same volume twice when you do that
 2 years ago

sauravshakya Group TitleBest ResponseYou've already chosen the best response.0
the answer is 8pi
 2 years ago

amistre64 Group TitleBest ResponseYou've already chosen the best response.1
dw:1342094460320:dw if we do shells:\[\int_{0}^{2}2pix(4x^2)dx\] \[2pi\int_{0}^{2}x(4x^2)dx\] \[2pi\int_{0}^{2}4xx^3\ dx\] \[2pi\left(\frac{1}{2}4x^2\frac{1}{4}x^4\right)_{0}^{2}\]
 2 years ago

virtus Group TitleBest ResponseYou've already chosen the best response.0
oh i think i understand. I apologise amistre64 if i sounded rude before. I had no intentions whatsoever to offend you.
 2 years ago

amistre64 Group TitleBest ResponseYou've already chosen the best response.1
no offense taken :)
 2 years ago

virtus Group TitleBest ResponseYou've already chosen the best response.0
@amistre64 i thought it was around y axis, shouldn't be dy not dx ?
 2 years ago

amistre64 Group TitleBest ResponseYou've already chosen the best response.1
depends on your method; i used the shell method, which opens up along the x axis the disc method would travel along the y
 2 years ago

amistre64 Group TitleBest ResponseYou've already chosen the best response.1
teh disc method we would have to convert y=x into its inverse x=y, which isnt that hard to do, but just takes extra steps :)
 2 years ago

virtus Group TitleBest ResponseYou've already chosen the best response.0
oh i see, so for the shell method where does the x come from in x(4x^2)
 2 years ago

amistre64 Group TitleBest ResponseYou've already chosen the best response.1
think of the shell method as finding the area of a sheet of paper, or a flattened out tin can. the width of the paper is the circumference of the base circledw:1342095061762:dw the height of the paper is the function that it hits along the way. Area = base (2pi x) * height (f(x))
 2 years ago

amistre64 Group TitleBest ResponseYou've already chosen the best response.1
dw:1342095194082:dw
 2 years ago

virtus Group TitleBest ResponseYou've already chosen the best response.0
OH I GET IT NOW ! thanks @amistre64
 2 years ago

amistre64 Group TitleBest ResponseYou've already chosen the best response.1
youre welcome
 2 years ago
See more questions >>>
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.